hi everyone mrs h again trying to go through some additional lessons on our ka acid-based lessons kind of applying some of that aerial atom resonance induction and orbitals the aerial system in determining strengths of acids and just really comparison the ability to stabilize their conjugate base we can also apply those same rules or same ideas of area into predicting the side of any equation that would be favored at an equilibrium in a previous section we talked about a quantitative way to determine the equilibrium push and that was using the pka chart and we said that when comparing the acids and again noticing that we have two acids in this acid-base equilibrium h a or h b whatever that might be and we looked up the pka values and we said let's suppose we had a pka value here of approximately 30 and this one was approximately 50. those are larger numbers so these would be weak acids but definitely we saw that the equilibrium would favor the production of the weaker side so the equilibrium lies on the side of the weaker the weaker acid and so we did that using pka values the higher pka will be favored since that's the weaker acid and then you can think of the relative stability of the bases their conjugate base b negative or a negative knowing that the more stable the conjugate base the more strong the acid is so this must be a more stable conjugate base less stable conjugate base because uh let me just write cb for conjugate base we know that the less stable conjugate base would have the weaker acid so what about applying these reo and kind of predicting equilibrium sides and let's just try to like do these without a pkhr and just kind of go through the logic of reo so i'm going to determine which side of the equilibrium is being favored and first of all let's hook together the conjugate pairs so i can identify the two acids so what are the conjugate pairs we're finding the acids so here i have a structure that has an oxygen i'm just going to point out really something we should see this oxygen forms conjugate pairs and then notice here this is a sulfur and those are going to be conjugate pairs everything else in this chemistry is exactly the same so this cyclopentane see how it has a five-membered group i'm attaching conjugate pairs the one with more hydrogen is always the acid so this is its conjugate base and if i think here between this and this those are two conjugate pairs they only differ by the presence or absence of a hydrogen this would be the acid it's actually the conjugate because it's on the right side and then this of course would be behaving as a base so we find the acids and now without a pka chart i mean i would have just said go to the chart and find their ka values or their pka values and decide which one is the weaker knowing that that would be the side being favored but we don't have a pka chart so let's use and kind of influence area to decide which side is now going to be favored and it has to do with the ability to stabilize the negative charge so what did we say the difference was well here's a base the conjugate base here has a negative charge on a nitrogen that is going to be resonant stabilized notice it's next to a sulfur that's involved in a pi bond so this is resonance stabilized and the atom it will be stabilized with is a sulfur on this side this is a conjugate base and the atom that it's on is a nitrogen so in terms of the atom and that's the same thing and they're both attached to an n in terms of resonance yet that's the same right because we can see the electron we can see that it will be resident stabilized for both of those so yes that's really the same they're both resident stabilized so that's not really a deciding factor so what about the induction effect you know thinking about um are there any electron withdrawing groups are the orbitals anything to consider and as i realized about resonance in atom i don't really need to go any further because resident stabilization across a larger atom will allow me to make my decision of what's the more stable conjugate base sulfur is the larger atom compared to oxygen so this is also resident stabilized but it's being stabilized by a smaller oxygen atom as compared to the sulfur which is the larger atom so yes they're both attached to nitrogen yes they both exhibit resonance really induction in orbitals don't play a role here so i have to decide between the sulfur and oxygen who's going to be better at at stabilizing the delocalized electrons and that means that the sulfur wins right it's the larger atom a greater surface area is going to help stabilize the negative charge better so that means this is a more stable base meaning that its acid over here is a stronger acid which now helps us remember that the stronger acid always pushes towards the weaker side so this equilibrium is going to be lying to the left which has the weaker acid and i did this without using a pka chart so we went through a series of steps without a chart and just kind of talked through how we could decide which one would be a more stable configuration we found the two bases and we did so really by just hooking together the conjugate pairs the base has one less hydrogen and we said since they're both on a nitrogen atom we had to decide based on resonance even though they're both resident stabilized we said sulfur beats oxygen in this resonance stabilized structure because it is the larger atom and a larger surface area is going to help stabilize that delocalized set of electrons better and therefore since this is a more stabilized base it came from the parent who was a stronger acid and just kind of applying the more stabilized stabilized base is going to have the equilibrium lie on the same side this equilibrium is going to be favoring the left side of the of the uh double arrow so to kind of think about that you'd have an arrow distribution showing the left side is dominating we can apply the reo system to predict the position of equilibrium for each of the following reactions and i just pulled one from your homework so what i've done is kind of set up an l this is an alkane this is sp3 hybridized and this is just the presence or absence of its hydrogen so just to kind of think about conjugate pairs those two are called conjugates the acid is the one with more hydrogen on it and so this therefore is its conjugate base that makes these two conjugate pairs that means the one with more proton is the acid and over here is its conjugate base look and find those bases and see whoops which one is better stabilizing the negative charge reo the atom that the negative charge is on in the first structure the atom here is on a carbon over here the negative charge is on a nitrogen right here we can stop right there is no resonance there is no induction there is no orbitals to consider so i'm looking at the very first criteria the atom the more stabilized will be the more electronegative element this is the more stabilized base the negative charge is being distributed over the more electronegative element the more stabilized base told us that its conjugate acid was stronger and therefore this acid must be the weaker acid we know that we're going to favor the side that's showing us the more stabilized base that we're showing the side that is producing the weaker acid and i just said that same thing two different ways stabilized base is the side that's favored so clearly we see that this equilibrium will be favoring the right side so the equilibrium arrow shows more product than reactant at equilibrium same idea just kind of applying uh what we look at in terms of of equilibrium to ario and deciding which one would be the more highly stabilized conjugate base another application of reo is choosing the appropriate reagent for a proton transfer for example we might be asked something like is water a suitable reagent for deprotonating the acetate ion the acetate ion is the resulting conjugate base from acetic acid c-o-o-h and so what we're really asking ourselves is to consider the bronsted-lowry acid base and think think this through is this going to work so we have a water molecule hoh and it's going to be in dynamic equilibrium with the acetate ion and there's the negative charge so remember bronsted-lowry says and proton transfer will occur and that's our whole chapter right thus far to get to lewis but proton transfer always involves two arrows right the electron rich area on the base is going to reach out for the proton on the acid and when it does so this bond collapses and we form conjugate pairs the conjugate base of water is hydroxide the conjugate acid of the acetate ion is acetic acid so here we've just protonated the acid there's that proton on the oxygen right so we've really just set up conjugate pairs will this reaction occur and if it does that means that the base that's produced is a very stabilized base now i forgot the negative sign there we go let's compare o h negative to the base of the acetate all right those are the two bases in our structure ario a r i o the very first letter is a for atom the negative charge on both of these bases is on the same atom [Music] so that's really not helpful let's go to the next letter r reo resonance which one of those is resonance stabilized well clearly you can see the negative charge here on this oxygen has the ability to be resident stabilized because the carbon next door is involved in a pi bond so yes this is resonance stabilized whereas this is not resonance stabilized so this must be the more stable base which means its parent acid was stronger and both of those decisions let us realize that the equilibrium always pushes towards the weaker side the equilibrium always pushes towards the more stabilized base so this equilibrium is lying to the left is water a suitable reagent for deprotonating the acetate ion and the answer is no because this reaction did not proceed in the forward direction with any kind of certainty we're saying no this really didn't happen so the resonance structure of the acetate ion showed that it was the more stable configuration and when we realized that the left side of the arrow is favored and golly no we don't have any of that forward direction so the equilibrium favors left side if we wanted to deprotonate the water that is not the correct selection of reagent is this an appropriate reagent selection all right so here we have let's say we're going to take some water and i want to protonate this molecule that contains nitrogen and you see how there's a negative charge so to have a negative charge it actually has two sets of electrons right nitrogen needs three bonds and one lone pair so if it's negatively charged it has two sets of dots and one and the two bonds it is one bond deficient so when this occurs this negative region on the nitrogen is going to reach out for the hydrogen and it will collapse the bond onto the oxygen so we have our conjugate base of water hydroxide and we would have the conjugate acid form [Music] because i get in emails and so there's the acid-base conjugate pairs two electrons for this proton transfer what we're really being asked is does this reaction proceed to the right is this an appropriate reagent means we're going to be favoring the right side proton transfers are acid based chemistry they involve two reaction mechanism arrows this is a base and this is a base reo which one of those is stabilizing the negative charge better right off the first letter it says atom this is being stabilized by a nitrogen atom and this is being stabilized by an oxygen atom they are different from each other so i can make a decision right with the very first letter of arya i don't even need to progress because oxygen is the more electronegative element this is the more stabilized structure and therefore this is the um you know just thinking about the favoring side we know that it will favor the more stabilized conjugate base think about what i just said this is the stronger acid because it produces a very stabilized conjugate base compared to this which is a weaker acid and the equilibrium lies on the weaker acid side so definitely we could see this equilibrium favoring the right side it's favoring the more stabilized conjugate base it's favoring the weaker acid and so yes this is a reagent that would work great in protonating that base because i'm actually seeing a reaction proceed in the forward direction another application would be selecting a reagent to protonate the following molecule so what i want to do is kind of go from this base and produce its conjugate acid so i want to add that proton back on alrighty so i'm really asking you what can i place here as an acid that when it forms its conjugate base on this side we end up with you know conjugate pairs this conjugate base has to be very stable all right just kind of thinking that through well this is the game and i just put a little snapshot of the pka chart because in order to select a reagent you got to use your pka chart to even know what are some choices and i'm just looking down here i know i need an acid so i know i'm going to be looking in the left column because this says i want to protonate to protonate that has to be the base so these electrons here are looking to attach a hydrogen back so i know that you're going to be identified as a base so i got to look down the left column on my pka chart and find some acids and i have to look at these and decide which one's going to be better do i want to look above acetylene c2h2 or do i want to look below acetylene for an acid that will protonate when the answer says we want to make sure that we're producing an acid that's weaker than what we started with and so i want to look above acetylene and let's just go like one above shall we let's say i'm going to put in a reagent that is a ketone and next door to it here is this hydrogen that's the one i'm selecting right here that would be a reagent it's a ketone because this is a carbonyl attached to two other carbons it's a functional group of a ketone i could pick the alcohol that's tertiary i could pick the alcohol that's primary this carbon is attached to three other carbons tertiary alcohol this is a primary alcohol it's attached to just one other here's just a simple water molecule any of those work because when i have the acid it's pka of 19.2 and i compare that to the conjugate acid of acetylene which is 25 i am pushing towards a weaker acid i am pushing towards a more stabilized conjugate base because this happens to be resonance stabilized when i remove this proton i come up with a conjugate base that will be resonant stabilized and that's also favoring the right side of the equation so any acid that has a pka showing a stronger acid meaning a smaller number will be a successful reagent and putting the proton back on and so i just used a pka chart what would not work is picking an acid that has a you know it's too weak to be able to protonate that acetylene i'm going to talk a little bit about some topics here at the end of our chapter and really kind of laying some foundational work for mechanism the first of these topics and talk about leveling effects solvation effects counter ions which i call spectators and a brief little talk about lewis acids and bases to round out our chapter the first of the effects is we start selecting reagents and the medium to run equations in will be a leveling effect let's decide what that means it says to define the term leveling effect it's an effect that prevents the use of bases that are stronger than the conjugate base of the solvent employed okay so let's think about what i just said to do bronsted-lowry acid-base theory we need a solvent even if i were to just draw a simple acid-base theory where we get a h3o plus and a cl negative in this example we need some sort of medium for ions to swim around in in that classic example of acid-base chemistry water is the solvent see if i were running these in in a gaseous medium or you know some sort of solid medium molecules don't have the ability to ionize and exchange partners they have to have some sort of solvent some medium to allow the kinetic motion of the molecules to collide and for bonds to break we have to have a medium for the for the solution to allow proton transfer so that's what a solvent is for it's the medium that allows molecules to collide through one another and to break bonds and to reform new bonds has to incur in some sort of medium typically you know a very common medium is a water for acid-base chemistry but sometimes water itself isn't a good choice and let's talk about why when we discuss leveling effect the key here of selecting a solvent in the lab to run your acid-base reactions the solvent should be able to surround the reactants kind of help to stabilize them based on polarity and facilitate their collisions but it shall itself should not react it has to not participate and consume the acid or basin reaction because water really is an acid or a base that word we learned in gen chem was amphoteric it can act as an acid or a base a proton donor proton acceptor it has a leveling effect on very strong acids and strong bases acids stronger than hydronium cannot be used in a water medium here's hydronium on your pka chart if i'm using an acid that's stronger than hydronium it actually consumes that acid and takes it out of the reaction bases that are stronger than hydroxide so let's find hydroxide on our pka chart and it says here's hydroxide for example these are the base side and base is actually increase in strength as you go down anything below this is a stronger base bases stronger than hydroxide cannot be used in a water medium for the solvent and i'd like to describe why in the next few slides so selection of the solvent is critically important and that's what we refer to as the leveling effect we want to be sure we're selecting a solvent that actually promotes the reactions instead of destroys the reaction let's dive into that topic appropriate use of water as a solvent when the base is not stronger than hydroxide all right so here we have the acetate ion this is a conjugate base of the acid acetic acid these two are referred to as conjugate pairs in the bronsted-lowry theory water h2o has a conjugate of hydroxide those two are conjugate pairs when we identify the acids h2o is acting as an acid and acetic acid cooh is acting as the acid i've identified the acids in both sides and i pull out the pka chart and the pka chart says the stronger acid is acetic acid it's going to stabilize its conjugate base and clearly we can see that the base is stabilized through the resonance of that oxygen even though we have the same atom stabilizing right i'm stabilized by oxygen in both of these bases the resonance structure makes this a more stable conjugate base and clearly we see that the equilibrium lies [Music] the equilibrium lies on the more stabilized side and that's the left side of this equation so the left is being favored what that means is that when i put water into this solution i am not destroying the acetate and that's important because let's say i want to do a next step i want to actually have acetate be protonated by something else i need a solvent to do that i don't want to put water in as the solvent and have it destroy the acetate by making the reaction push right and taking it out of solution i can then take the acetate base and select an acid not water but an appropriate acid as we had done in the last section and actually produce conjugate pairs water can act as the as the medium the solvent and not participate in the acid-base chemistry because it will not destroy the acetate ion the solvent must keep the equilibrium on the left side if you add a solvent and it pushes the equilibrium to the right side you destroy the original molecule and the reaction that you want to have happen will not proceed let's take that example here we have a very strong acid it's sulfuric acid pka of negative nine isn't that at the very top of your chart so if this is an acid water would be acting as the base producing the conjugate acid oops i'm sorry that's the conjugate base these two are conjugates and the conjugate acid of hydronium so when i find those two acids i'm comparing hydronium pka of negative 1.7 and sulfuric acid with its pka published at negative 9. clearly you see that the equilibrium is going to be pushing to the right it's going to favor the weaker acid it's going to favor the more stabilized conjugate base notice this conjugate base when i compare water this will have resonance ability to delocalize actually across two different pi bonds so a very stabilized conjugate base so what have we done if my goal was to have sulfuric acid react with something you know let's say i want to have it react with ammonia let's actually do some chemistry where i want to add an acid and a base and i need something for the molecules to be in i need a solvent if i put that sulfuric acid into water i've destroyed it because it gets consumed when the equilibrium favors the right side so this is no longer there what's in solution is its conjugate base and therefore i don't really have the starting material to react with the next reagent so when i select a solvent i want to consider the strength of that solvent to make sure it doesn't consume the acid or the base i want it to keep the equilibrium to the left so that that molecule is not destroyed by the presence of the solvent and you can consider these as well bases any base stronger than hydroxide cannot be used in water because for example we wouldn't be able to perform the following acid base reaction so for instance if i had here's an acid this is a base we formed a conjugate base and a conjugate acid that's the chemistry i want to have happen all right so let's suppose i place you know this particular base in a water solvent if i did this n going off in both directions here's the negative charge and i place water as the solvent the acid-base chemistry occurs to create conjugate pairs we would place produce the conjugate here with the hydrogen on it and again a lone set of dots and the conjugate base over here of o h negative so i would be comparing the stability of the base that has nitrogen stabilizing the negative charge and i would compare it over here to this base which has oxygen stabilizing the negative charge since oxygen is more electronegative than nitrogen these are the two bases the more stabilized structure stable eyes i don't think i spilled that right may i try again there we go the more stabilized base is going to say we're favoring the right side of this equilibrium and therefore if i favor the right side i've destroyed this base and in its place we have hydroxide well that's no good i would not be able to carry out this reaction because this would no longer be present it would have been exchanged with hydroxide and i don't have any of the desired outcome on the right hand side so water cannot be used as the solvent in this particular example because it destroyed the base and replaced it with the hydroxide polyatomic ion and so you'll kind of read through and say we need to show a better choice you know working with this particular substance you know you can see that we're going to be favoring the left side of this equilibrium based on the pkas or the stability of you know the hydroxide ion there and so we'd be we'd destroy it and therefore this reaction wouldn't occur um what could we use in its place you know anything that would have an opportunity to set up a a solvent that would not destroy so that would be anything stronger than hydroxide oftentimes we use liquid ammonia with amide so the leveling effect kind of describes for us the careful selection of a solvent as to not destroy one of the acids or bases and take it out of the reaction because they're so similar areo cannot really be used to explain the pka difference between the following ethanol and tert-butanol and this leads us to talk about a second effect the first being leveling the second being solvating here we have tert-butanol one two three four carbons in that structure that's the prefix butte and i can also see this alcohol functional group with the ol ending and we call this a tertiary alcohol the tertiary alcohol means that the carbon bonded to the functional group of oh that's this carbon is bonded to three other carbons this carbon attached to the alcohol functional group is attached to just one other carbon it's called a primary alcohol if we went through areo why do we see a difference in the acidity when they're bonded to the same atom none of them exhibit resonance there are no inductive effects and they're in the exact same orbital you see how close ario is to both of these so what can we do to explain what makes one more acidic than the other and clearly by looking at the proton here this is the more acidic proton but why and again the answer comes back to the solvent the ability of the solvent to stabilize the conjugate base's negative charge helps to create a stronger acid look at this diagram with me this is our tert butoxide right this is the negative ion the conjugate base of that alcohol we we saw on the previous slide this is the conjugate base we saw of the primary alcohol notice this big area over here presents a very bulky sterically hindered air area i'm getting all kinds of emails this here is a big bulky area so really the only interaction that this negative ion has this is the oxygen part right so that's all of the negative ion the only interaction that this solvent might have and if it's water for example we'd want to align the hydrogens there to help stabilize the charge right hydrogens are partial positive so water would be trying to align itself to place the hydrogens next to it just to help stabilize with these hydrogen bonds now it's not doing so very well because this big bulky area of this tert butyl big bulky base area you'll hear me say that a lot this is a big bulky base it has a steric hindrance because of its you know lots of carbon in that area and it makes the water molecules very difficult to have access to this oxygen to help stabilize it whereas if i have kind of a less hindered area the solvent has a greater surface area available to it to help distribute that electron charge and again especially if this is water as the solvent which it probably would be here you're setting up these little attractions called hydrogen bonds with a greater surface area that water can set up the stability this ends up to be a more stable negative charge and therefore you know the the solvent itself has the ability to stabilize the negative charge you know and it's not reo with an s for solvent so you have to kind of consider that when everything else is failed what is it in you know is it in a molecule such as a water solvent then help can to distribute these ion dipole attractions and if so you're going to see this more stable structure being the least sterically hindered structure so for example which one of these is the more acidic compound you have a carbon to carbon o-h and just plain h-o-h and i didn't mean to make that linear it's you know it's a zigzag as well um but again notice this chain here this chain is kind of a non-polar area it's the hydrocarbon chain which kind of creates you know a bulky area whereas this guy has no steric hindrance at all making this proton more acidic than this proton the less sterically hindered it is the more acidic the more stabilized the molecule becomes so i'll just say less steric hindrance to allow stabilization by the solvent we selected water as being more acidic counter ions i often call those spectator ions these are ions that are necessary in our chemical acid-base reactions just to keep the electrical charge neutral spectator ions do not participate they are simply there to keep the electrical charge so here i see a sodium amide really you can see that as two separate ions a sodium and an amide and of course here's your water molecule on this side you have ammonia and on the other side here you have sodium hydroxide i just want you to notice what's happened with sodium sodium is aligning itself first near this amide and really just think of these as two separate entities one is called a cation a spectator the other is called an anion they're held together by electrostatic charge so it's there to stabilize the negative charge right i can't just go to the shelf and pull off a negative ion it has to have a first name but as this proton is then transferred and this bond collapses and we form hydroxide where does the sodium then migrate to well based on the electron distribution this sodium ion is now going to migrate next to the hydroxide ion just to help stabilize its charge create a neutral compound overall but it did not participate so those are called counter ions they simply counter the balance of charge you might hear them called spectator ions they're only there to counter the charge we do not necessarily have to write them in the reaction so if you see some example of like lithium which is plus and acetate acetate would be a carbonyl group leading out to the oxygen that would be an example of a lithium and then this would be its conjugate this base part would be the acetate and if you see that react with water the acid-base proton would transfer so you'd see the oxygen reach out for this proton and the bond collapse on the opposite side now you'd form the conjugate acid of acetate which is acetic acid oops that's all one big bond so that kind of separated for whatever reason when i drew it and then over here you'd have a protonated deprotonated water and then of course the sodium would just migrate over there so the lithium would just migrate over there just some kind of usually an alkali metal that's just there to stabilize charge in this case lithium ion is called a counter ion or it's called a spectator ion and our chapter is going to wrap up sharing a third working definition of acid-base theory the common one is called the arrhenius definition arrhenius says acid starts with an h bases end with an o h we talked about at great length bronsted-lowry being proton transfer acids donate protons bases except protons and the third working definition we should be familiar with is the lewis acid and the lewis base this is the same gentleman that gave us lewis dot structures right so that's a lewis dot structure for chlorine these are the lewis acid base definitions a lewis acid accepts a pair of electrons a lewis base donates a pair of electrons under the bronsted-lowry definition anything that is a bronsted-lowry acid is still a lewis acid anything that was a bronsted-lowry base is still a lewis base it fits both definitions for example in this definition water is acting as a base hcl is acting as an acid because we've had a proton be transferred this here hcl was a proton donor over here this was a proton acceptor that's the bronsted-lowry acid-base theory and on the opposite side we have conjugates now keep in mind bronsted-lowry is the only definition that has conjugate pairs arrhenius no lewis no bronsted-lowry yes conjugate pairs this is the species that forms on the right side the conjugate acid forms from the base the conjugate base forms from the original acid with the lewis theory we're not looking at the right side we're only identifying acid base here now look at how we could also envision this the oxygen is donating a pair of electrons it is an electron donor electron pair donor as it forms a bond with the hydrogen that's the electrons that were donated to make a shared pair on the opposite side the acid accepts an electron pair the hydrogen accepted the electron pair as it formed the bond resulting in the transfer over to the hydronium so they're still going to work bronsted-lowry acid base are the same as lewis acid and base but now let's take a look at what makes lewis acid and base an even broader definition than bronsted-lowry and really this is the classic definition where you look more of a combination reaction where you have a single product on the right hand side that really is unique or key for the lewis theory arrhenius and bronsted-lowry working definitions always had a plus b gives me c plus d you'd have two products on the right hand side the lewis theory allows us to look at more of a combination or a synthesis pattern of reaction where a single product is formed here we have an electron rich area on the water and here we have an electron deficient area on the boron and again that's really just inductive forces here pulling the electron density away from boron making it a positive charge so as these electrons reach out for this positive area on the boron a bond forms because the electron pair donor came from water water is acting as a lewis base because the boron accepted the pair of electrons bf3 is acting as the acid and you produce a single product where a new bond has formed between the electronegative rich oxygen and the electron deficient boron and one product formed identify the acid and base in the lewis theory with this reaction remember you can detect lewis acid-base theory because it forms a single product there are no conjugate pairs in the lewis theory so that means one on the left is the acid one is on the right one one is on the left is an acid the other must be the base look for the electron rich area on the oxygen look for this electron deficient area on the boron i can see a bond forming between the oxygen and the boron and that's this bond right here it results in a positive charge on the oxygen the formal charge is plus one on the oxygen the formal charge on boron becomes a minus one but a new bond did indeed form this right here was the electron pair donor that means this was the base and this right here was the electron pair acceptor meaning this one acted as the acid so the acid plus base combined to form a single product in the lewis acid base theory you have a couple more to kind of look at on your homework your skill builders i want you to find the electron deficient area on the aluminum and you can see the electron rich area on the oxygen and then just follow the electron flow you see how there's a new bond between the oxygen and aluminum that tells us exactly that this was the electron pair donor making this the base aluminum was the electron pair acceptor making this the acid here we have a ketone and notice the ketone here is has the oxygen even though they're not drawn we see oxygen up here and then we have a positive charge on hydronium and what do we see on the right side well i see conjugate pairs i don't see a single product like i did up here a single product is only unique to the lewis right this is unique to lewis but when i see conjugates i notice that i can see two species on the right hand side i have conjugate pairs i'm going to fall back to my bronsted lowry and say conjugates differ only by the absence or presence of a hydrogen and the one with more hydrogen is always the acid so that ketone must be the base this hydronium is acting as an acid forming its conjugate base and so thinking about the the actual chemistry you can see the oxygen reaching out for one of these equivalent hydrogen and the bond collapsing and you form the conjugate pairs so you could use either bronsted-lowry or lewis whatever you're more comfortable in if you see conjugate pairs forming if you see a single product form that's unique to the lewis theory as well oh my goodness we have done it we have looked at all of the content for chapter three you have done a brilliant job you need a rest i need a rest when ready i'll challenge you to start your next orion your wiley skills builder and please prepare for your chapter quiz come back when ready